The invention relates in general to a gear clutch and, in particular to a new and useful clutch having a clutch casing with internal teeth and at least one clutch hub which, due to its external teeth, sits in the casing coaxially and rotationally fixed to the casing, the hub having an axial annular groove which ends below the root of all the teeth of the clutch hub towards one side of the external teeth.
Such a clutch is known, according to the Clutch Atlas by A. Schalitz, 1975, A. G. T. Verlag Georg Thum, Ludwigsburg, page 15, FIG. 2.2-1. The axial annular groove therein together with a projection of a flange engaging it, serves to form a kind of labyrinth seal. The flange is attached to the clutch casing and closes the gear clutch off towards the outside. The material thickness between the annular groove and the root of the teeth of the clutch hub transmits, with sufficient safety, the maximum torque that can stress the teeth.
According to the same Clutch Atlas, page 21, FIG. 2.3-52, it is further known to mount one of the clutch hubs of the gear clutch rotatably on another hub fixed to the stub shaft of a motor or machine. The hubs have flanges which face each other and are interconnected by breakoff pins so that an overload can be prevented by breakage of the pins. This design requires many parts and the assembly is too long and too expensive due to the rotary mounting of the clutch hub. In addition, there is the danger that the pin fragments will leave their holes after breaking and be hurled away destructively.